Method of constructing tunnels



July 21, 1959 P. WASHABAUGH 2,895,299

METHOD OF CONSTRUCTING TUNNELS Fil ed June 24, 1955 11 Sheets-Sheet 1 a? BY Bu u.

July 21, 1959 E. P. WASHABAUGH METHOD OF CONSTRUCTING TUNNELS 11 Sheets-Sheet 2 Filed June 24, 1955 INVENTOR. [dam/ d Wasfiaboajfi BY (3 (MM ATTOF/Vi/J' July 21 1 959 E. P. WASHABAUGH 2,895,299

METHOD OF CONSTRUCTING TUNNELS Fi' led June 24, 1955 l1 Sheets-Sheet 5 IE=EEL IIIIIIIIIIIIHI llll Illillll IN VEN TOR B EDWARD F [MS/M3406 ATTOP/VEXS July 21-, 1959 E. P. WASHABAUGH METHOD OF CONSTRUCTING TUNNELS ll Sheets-Sheet 4 Filed June 24, 1955 ICE-:I

, INVENTOR. "EDWARD I? MSl/ABAl/G/l QW+ P J July 21, 1959 E. P. 'WASHABAUGH METHOD OF CONSTRUCTING TUNNEILS ll Sheets-Sheet '7 Filed June 24, 1 955 i 60 ljo 1 N VEN TOR. E: E mm P WIS/MBAUGH July 21, 1959 E. P. WASHABAUGH 2,395,299

METHOD OF CONSTRUCTING TUNNELS Fileq'June 24, 1955 11 Sheets-Sheet 8 Ilsa-.55-

' VEN TOR. .78 11v ATTORNEYS E. P. WASHABAUGH METHOD OF CONSTRUCTING TUNNELS July 21, 1959 ll Sheets-Sheet 9 Filed June 24, 1955 INVENTQR EDWARD I? (IS/#84067! a -wm r l ATTORNEYS uly 1959 E. P. WASHAB AUGH 2,395,299

METHOD OF CONS'fRUCTING TUNNELS Filed 'June 24, 1955 ll Sheets-Sheet 10 FLE:SE

y ,1959 E. P. WASHABAUGH 2,395,299

' METHOD or CONSTRUCTING TUNNELS Fil ad Jun'e 24, 1955 11 Sheets-Sheet 11 ESE TEE- BE IN VEN TOR.

0 M420 A WAfl/464((GH ATTOR/VIYS United States Patent 2,895,299 M'Errron 0F coNsraUcrmG TUNNELS Edward P. Washabangh, Saginaw, Mich, assignor to American-Marietta Company, Chicago, ill., a corpora-- tion of Illinois Application June 24, 1%5, Serial No.517,701 8 Claims. (Cl. 61-'45) This invention relates to apparatus for, and a method of, constructing tunnels, sewers, culverts, or other underground tubes from a plurality of tubular sections.

This application is a continuation-in-part of my copending application, Serial No. 410,252, filed February 15, 1954 and now abandoned.

Heretofore tunnels or other underground tubes of the character described have been constructed as follows: by the open trench method, digging an open trench and placing tunnel sections therein; by timbering, digging a tunnel pasageway and shoring the same up with timbers and then placing the tunnel sections therein starting from the far end; by jacking, which consists in shoving a plurality of tunnel sections forwardly as earth is removed ahead of the lead section; by building the same up from blocks, segments, or the like, laid up into tubular form within an excavated passageway; and by pouring concrete into tubular forms installed within an excavated passageway. The first three mentioned systems employ tubular tunnel ring sections and while each system has been widely used, each possesses disadvantages which are serious under certain conditions. At great depths, the open trench is prohibitively expensive; under certain soil conditions and for substantial distances, jacking is exceedingly difficult; and the timbering method is expensive and dangerous, particularly for great distances.

My improved method is designed to permit tunnel sections to be placed in position quickly and economically and following up directly behind the excavating and generally without any timbering being required.

My tunnel sections are pre-formed or precast into ring form. They may be, and preferably are, in complete ring form as shown in Figs. through 10, but they might be in the form of incomplete rings as shown in Figs. 34 and 35. The words tunnel ring section, or tubular tunnel section, are used herein to describe either the complete or incomplete ring form. These tunnel sections are substantially identical in size and shape. They are so shaped and so dimensioned that one tunnel section may, when disposed at a determined position with respect to another section, be passed therethrou-gh, whereby successive tunnel sections may be moved as needed through the completed portion of the tunnel and placed in position to extend the same along. Each tunnel section is so shaped and dimensioned as to exhibit a minor axis and a major axis and the outside dimension along the minor axis is less than the inside dimension along the major axis and the axial length of the tubular section is such that one section may be moved through another section when they are disposed in a determined angular relationship.

This system is capable of being readily combined with the jacking system in that the first few tunnel sections may be jacked into, position, but when this operation becomes difficult the remaining sections may be moved into place in the manner set forth. On the other hand, when jacking has proceeded as far as possible or practicable from a shaft, a new jacking operation can be started at the end of the completed section and pre-cast units of the shapes shown can be carried through the finished portion to the beginning of a new jacking operation.

This method of constructing a tunnel is desirable not only for the reason that the tunnel sections may be easily handled and moved into position but the work is carried on through the completed portion of the tunnel and the danger of injury to workmen is substantially minimized as compared with many of the old conventional systems. Finished lining is kept closer to the heading and all mate rial is handled through a finished tube of known structural strength.

This method of construction possesses another advantage in that each tunnel section is pre-formed or pre-cast and its fitness for use is readily determined before it is used which is not true where the tunnel is built up in segments or blocks. The preformed units can be inspected during their manufacture. Thus they have a known and definite structural strength which does not depend upon inspection in the tunnel where adequate inspection is difficult or impossible, particularly where smaller units or units which do not form a full ring are used. The total length of unlined tunnel to be supported during construction is greatly reduced as compared with certain common prior practices. The need for liner plates, timbering, shoring and bracing, if not completely eliminated, is always reduced.

Therefore, an object of my invention is the provision of an improved method for constructing tunnels whereby a complete and pre-formed tunnel ring section is carried through an already installed portion of the tunnel and into a heading excavated ahead of the installed portion of the tunnel and is then rotated and positioned in tubular alignment with the leading edge of the tunnel and drawn back against such edge to form a continuation of the tunnel. More specifically this object comprehends an improved method of constructing tunnels from pre-forrned tunnel ring sections of such elliptical or arc-like shape that one may be passed through another when corresponding axes are disposed perpendicular to one another, with a tunnel section while so disposed with respect to a plurality of already installed sections being carried through such installed sections and into a heading excavated ahead of the installed sections, and while supported in the heading from within the installed sections being rotated in the heading to a position of tubular alignment with the installed sections and thereafter drawn back against the leading edge of the installed sections to form a continuation thereof.

A concomitant object of the invention is the provision of a method as above described but wherein the rotation of the section being carried through the installed sections is begun while the section is within the installed sections, with the section being rotated about and closely adjacent a leading edge of the terminal installed section with the heading being excavated adjacent such edge to permit the section to be shifted across the tubular axis of the tunnel during such rotation and rotated into said excavation, thereby permitting the section to be rotated for placement against the leading edge of the tunnel in a heading of a substantially lesser length than where the section is carried completely into the heading before its rotation as with the first above mentioned method.

Another object of my invention is the provision of apparatus adapted to support a succeeding tunnel section for movement through a completed portion of the tunnel into the heading forwardly thereof, while the car remains within the completed portion of the tunnel.

Another object is the provision of wheeled vehicle apparatus which will support a succeeding tunnel section for movement through a completed portion of the tunnel into the excavated heading and which so supports or suspends the succeeding section within such heading that the succeeding tunnel section may be easily manipulated within the heading for accurate placement against the end of the completed portion of the tunnel to form a tunnel continuation thereof.

A still further object is the provision of wheeled vehicle apparatus having a. tunnel section carrying boom which projects forwardly of the vehicle and which boom is provided at its forward end with tunnel ring section supporting mechanisms adapted to support a succeeding tunnel ring section for substantially universal movement for placement against the end of the completed portion of the tunnel. The tunnel section carrying and supporting car is so counter-weighted and balanced that a tunnel section may be supported at the forward end of the boom forwardly of the car.

A meritorious feature of my invention is the provision on a car as described of a tunnel section supporting boom swingably mounted on the car and projecting forwardly thereof and provided at its forward end with a tunnel section engaging and manipulating head. Such head is so constructed and mounted as to interiorly engage a tunnel ring section to support the same at its center of mass for rotation, revolution, tilting, axial and radial displacement to move such ring section into alignment with already positioned ring sections. Such displacement is accomplished while the section is supported by the boom and while the car and the Weight of the section being positioned are within the com pleted portion of the tunnel and is accomplished in part by movement of the boom, movement of the head, and manipulation of the ring section relative to the supporting boom assembly.

An advantage of my invention is the provision of a car having a boom as aforesaid, which boom exhibits at its outer end a tunnel ring section supporting head slidably and rotatably mounted thereon for slidable and rotatable positioning of a tunnel ring section, and which head may be quickly and easily coupled with or 1111- coupled from a tunnel ring section to support or release the section from the head.

Other objects, advantages and meritorious features of the invention will more fully appear from the following description, claims, and accompanying drawings, wherein:

Fig. 1 is a schematic elevation partly in section through a portion of a tunnel showing a complete tunnel ring section being moved by a tunnel section supporting car through the completed portion of the tunnel;

Fig. 2 is a schematic elevation partly in section through a portion of a tunnel showing how the tunnel section carried by a tunnel section supporting car may be rotated ahead of the lead section of the completed portion of the tunnel to the position it will assume in use when placed at an extension ahead of the completed portion of the tunnel;

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. l, but showing the ring engaging pin in the outward position;

Fig. 4 is a vertical sectional view taken on the line 4-4 of Fig. 3;

Fig. 5 is a sectional view through one form of tunnel ring section suitable for use in this invention with the major axis of the ring disposed vertically;

Fig. 6 shows the ring section illustrated in Fig. 1 with its major axis disposed horizontally;

Fig. 7 is a sectional view through another form of suitable tunnel ring section;

Fig. 8 is a sectional view through a third form of tunnel ring section;

Fig. 9 is a sectional view through a further modified shape of ring section;

Fig. 10 is a schematic elevation of another shape of the ring section;

Fig. 11 is a sectional view taken on the line 1111-i of Fig. 1;

Fig. 12 is a schematic elevation partly in section: through a portion of a tunnel showing tunnel ring sec-- tions disposed at an angle to the vertical;

Fig. 13 is an elevation partly in section through a portion of a tunnel showing a complete tunnel ring section being moved by a preferred embodiment of the; tunnel section suporting and positioning apparatus; through the completed portion of the tunnel. This is. a more complete structural embodiment of the construc' tion of Fig. 1;

Fig. 14 is a cross sectional view taken on line 1414;

of Fig. 13;

Fig. 15 is a cross sectional view taken on line 15-15 of Fig. 14;

Fig. 16 is a cross sectional view taken on line 16-16 of Fig. 14;

Fig. 17 is a cross sectional view taken on line 1717' of Fig. 14 and showing the construction of the outer end. of the tunnel section supporting boom;

Fig. 18 is a cross sectional view through the tunnel sec-- tion supporting head taken on line 1818 Fig. 14;

Fig. 19 is a cross sectional view through the rear wheell truck section of the vehicle taken on line 1919 of Fig.. 13;

Fig. 20 is a cross sectional view taken on line 20-20; of Fig. 19 looking down on the rear wheel truck;

Fig. 21 is a cross sectional view taken on line 21-21. of Fig. 15;

Fig. 22 is a side elevation partly in section through the: forward end of the tunnel section supporting car showing. the driving connection for the front wheels thereof;

Fig. 23 is a cross sectional view taken on line 23-23.- of Fig. 22 showing the front wheel drive;

Fig. 24 is a perspective view of the cockpit and controlv devices of the tunnel section supporting car;

Fig. 25 is a top view of the tunnel section supporting: car taken on line 2525 of Fig. 13;

Fig. 26 is a schematic view of the driving connection: for the tunnel section supporting car between the wheels thereof and the driving motor;

Fig. 27 is a schematic view of the hydraulic system of the tunnel section supporting car;

Fig. 28 is a view of the tunnel section supporting head showing the employment of a spring chain to prevent movement of a tunnel section supported on the head;

Fig. 29 is a detail view of the manner of coupling the spring chain to the tunnel section supporting car;

Fig. 30 is a diagram of the electrical system;

Fig. 31 is a plan looking down on the boom assembly showing the ring as it is supported for movement through the tunnel;

Fig. 32 is a section through the heading and adjacent forward end of the tunnel showing the ring within the heading and rotated from the position in which it is carried;

Fig. 33 is a section through the heading and adjacent forward end of the tunnel showing the ring within the heading and rotated to position to be withdrawn against the completed portion of the tunnel;

Fig. 34 is a vertical cross section through the tunnel similar to Fig. 1 but representing a modified form of tunnel section;

Fig. 35 is a cross sectional view taken on line 35-35 of Fig. 34;

Fig. 36 shows a modified form of the tunnel section supporting boom, and together with Fig. 37 illustrates a method of positioning a tunnel section supported at the end of the boom against the leading edge of the tunnel where the heading is of a short length;

Fig. 38 illustrates another method of positioning a tun- .nel section against the leading edge of a tunnel where the heading is of a short length; and

dimension is indicated by the letter L.

stresses Fig. 39 illustrates still a third method er positioning a tunnel section against the leading edge of a tunnel where the heading is of a short length.

A tunnel ring section utilizable in the invention has to be of such a shape and so dimensioned that one ring section when disposed at a determined relative position with respect to another identical ring section may be passed therethrough. As shown, each tunnel ring section constitutes a full ring except in Figs. 34 and 35. Each section exhibits a major axis and a minor axis. In Figs. 34 and 35 the tunnel sections are incomplete arch shaped ring sections. The outside dimension along its minor axis is somewhat less than the inside dimension along its major axis and the tubular axial dimension or length through the ring is such that when one ring is disposed in a vertical plane with its major axis disposed vertically, another identical ring may be passed therethrough by disposing it in a vertical plane with its minor axis vertical and with its major axis horizontal and extending substantially parallel to the tubular axis of the first ring. It is, of course, obvious that the second ring could be passed through the first ring even though the first ring were disposed in a horizontal plane or in any other manner so long as the relative disposition of the two rings was preserved. It is apparent that rings may exhibit the shape and dimensions above set forth and vary somewhat in shape from each other. Generally the ring takes an oblong form, whether it is a variation from the square or from the circle.

In Figs. 5 and 6 the ring sections are oblong in the sense of a departure from the circle being of a generally :oval shape. In Fig. 7 a generally oval ring has its bottom flattened. In Fig. 8 the ring is of an egg shape. In Fig. 9 the ring is generally oblong having a bottom shaped somewhat lilce the ring of Fig. 7 with the remaining portion of the ring being arcuate. Fig. 10 shows a rectangular ring. Figs. 34 and 36 show incomplete archshaped rings.

It will be noted that in each of these figures, there is a major axial and a minor axial dimension and that the minor axial dimension on the outside measurement is less than the inside measurement of the major axial dimension. In Figs. 5, 7, and 8, the major inside axial dimension is vertical and is represented by the distance B and the minor outside axial dimension is horizontal and is represented by the distance A. In Fig. 6, the major axial inside dimension is also represented by the distance B but is horizontal and the minor outside axial dimension is also represented by the distance A but is vertical. The same is true of Fig. 9. In Fig. 10 the same letters are used to indicate the major inside axial dimension and the minor outside axial dimension.

.In each figure where it is shown, the axial tubular It will be seen that there is a definite relationship which includes all three dimensions. In other words, the axial tubular dimension cannot exceed a certain figure, depending upon the other dimensions, if one tubular section is to be passed through an identical tubular section. Tubular sections will be provided in the sizes and shapes desired depending upon the type of underground tube to be built, but the relative dimensions and shape will be as set forth.

In the several figures, and particularly in Figs. 1 and 2, each ring section is indicated by the numeral 20. These sections may be formed of concrete, reinforced concrete, vitrified clay, steel, iron, or any other standard material. The sections are pro-formed or pre-cast and may be made in any suitable manner. Due to the pre-formation of the sections they may be readily inspected prior to use. In Figs. 1 and 2 the several ring sections are shown as having axial faces which are stepped or rabbeted so as to interfit together as illustrated. In these two figures the several ring sections are disposed in a vertical plane. The several tunnel sections may, however, be arranged as shown in Fig. 12 in which the sections are not in a 6 vertical plane but at an angle thereto so that the crown of the section overhangs forwardly and offers some protection.

The method consists of carrying each ring section needed through the finished portion of the tunnel by so disposing the ring section to be transported, as heretofore described, that it may be moved through the completed portion of the tunnel and after it is moved therethrough into the heading and while it is supported. disposed within the heading but with the Weight taken from within the completed portion of the tunnel rotating and otherwise manipulating such ring section to line it up with the ring sections already in place. The ring section being transported may be carried by Wheeled tunnel section supporting and positioning apparatus such as generically illustrated in Figs. 1 and 2. In Figs. 13-29 a preferred structural embodiment of such apparatus is illustrated.

In the schematic form of tunnel section supporting car, illustrated in Figs. 1 and 2, the ring section 20 is supported by a strut 22 carried by a forwardly projecting boom 24 which is in turn supported by the upright standard 26 of a tunnel section supporting car 28. The tunnel section supporting car may have its rear end 30 weighted by mounting its engine and machinery therein. The strut 22 is shown as being journaled upon the ball 25 of the arm end 24 so that it may be rotated thereabout. The arm 24 is supported by the standard 26 to be raised or lowered or otherwise shifted as desired.

The boom itself is provided with a bend or curvature therein indicated as 27 which permits a ring section to be swung to the position shown in solid line in Fig. 2. The opposite ends of the strut 22 are provided with ring carrying pins 32 held outwardly by springs 34 so that the pins 32 may be projected through apertures 36 formed at diametrically opposite points in a ring section 20, as shown in Figs. 1 and 2, whereby the strut serves to securely support a ring to be lifted and moved as desired by the strut. To hold the pins 32 at adjusted positions, each pin 32 is provided with a locking pin 38 adapted to be received within a slot 40 so as to hold the pin retracted against the spring 34.

When a ring is picked up by the tunnel section supporting car and mounted upon the strut 22 such ring is swung to the position shown in Fig. 1. In Fig. 1 the rings that have been placed to form the tunnel are shown disposed with their major axes vertical. The ring being transported is disposed with its minor axis vertical and its major axis substantially parallel with the tubular axis of the tunnel. The ring is moved by the car to the position shown in Fig. l with the ring in the unlined heading portion of the bore ahead of the completed tunnel portion. The ring may there be rotated about the horizontal axis to move it to the position shown in solid line in Fig. 2. It may be rotated from such solid line position of Fig. 2 to the dotted line position of Fig. 2. The ring may be shifted otherwise as desired to align the same with the completed portion of the tunnel.

The tunnel section supporting car may be backed up to withdraw this supported ring section into axial abutment against the forward section of the completed portion of the tunnel. These changes in position of the ring section from the position for transportation through the tube to its final position as a part of the completed tube can be made in the order described or in various combinations or stages which accomplish the same pur pose. The method applies to the transportation of any ring section shown in the figures of the drawing, as, for example, ring sections such as shown in Figs. 7, 8, 9, and 10.

The aperture 36 in the wall of the ring section serves not only the purpose of mounting the ring sections upon the pins at the ends of the strut but also serves as a discharge outlet for grout to be pumped through to the and is indicated at 28 outside of the liner. It would also serve as an exit for the pumping of water through to lubricate the outside of the liner if the jacking method were being employed in jacking successive portions of a tunnel along in the .manner heretofore suggested. Such aperture 36 might,

however, extend only part way through the ring, extending only such distance thereinto from the inside as to serve as a seat for the supporting pin 32.

It will be noted that the ring is supported from its center of mass so that it may be readily manually rotated about different axes of rotation to align it with the completed portion of the tunnel. This is a matter of importance to accurate, easy alignment.

In Figs. 34 and 35 the tunnel sections are indicated at 20*. They are arch-shaped incomplete rings. The car is illustrated schematically as it is in Figs. 1 and 2 A boom 24 projects forwardly from the car. An arm 22 is pivoted on the outer ball end 25 of the boom. The ends of the arm 22 are provided with pins or reduced diameter extensions 32* to engage the tunnel ring sections. The tunnel ring section is transported and manipulated as shown and as described heretofore in connection with the rings of Figs. 1 and 2. The two ends of the arch-shaped ring may be mounted on concrete shoulders or the like 21.

In Figs 1329 is shown tunnel ring section supporting and positioning apparatus of a commercial character. In Fig. 13, the car is shown as supporting What is to be termed a succeeding tunnel ring section for movement through a completed portion of the tunnel. The succeeding section is shown as supported partially Within the completed portion of the tunnel and partially within the heading ahead of such completed portion. The section is shown as supported in the same plane as the succeeding section shown in Figs. 1 and 2, i.e., with the corresponding axes of the succeeding section and the installed sections being perpendicular and the major axis of the succeeding section parallel to the tubular axis of the succeeding section parallel to the tubular axis of the installed sections. The forward end of the car is to be considered the right hand end as shown in Fig. 13, and the rear end of the car is to be considered the left hand, as shown in Fig. 13.

As is more particularly shown in Figs. 13 and 23, a track 37 comprising a pair of rails 38 and 40 is laid in the bottom of the completed portion of the tunnel. The car, generally indicated as 42, is adapted to travel over this track. Four wheels mounted upon a pair of trucks are adapted to support the car upon the track. One pair of wheels, 46 and 48, shown in Fig. 19, is mounted upon opposite ends of an axle 50 which is secured by a pair of bearings 54 and 56 to a block 58 journaled upon a shaft 60.

As shown in Figs. 19 and 20, the rectangular block 58 is pivotally mounted upon the shaft 60 which is supported between a pair of cross members 62 and 64 which form a part of the car. The car 42 is provided with a pair of longitudinal frame members 66 and 68 which extend along the opposite sides thereof and to which the cross members 62 and 64 are secured. The wheels 46 and 48 (Figs. 19-20) exhibit peripheral flanges 70 and 72 which overlie the outside edges of the rails 38 and 40. The wheels 46 and 48 thus pivotally support the car at the rear thereof.

The forward end of the car is supported by a second pair of wheels 74 and 76 (Fig. 23) which are fixedly mounted upon an axle 78 (Fig. 22) which is in turn .rotatably mounted in the bearing blocks 80 and 82.

The bearing blocks are spaced apart as shown in such Fig. 23 and are secured to the rectangular frame members 84 and 86 mounted on the underside of the car 44. The Wheels 74 and 76 are provided with peripheral flanges 88 and 90 which overlie the outside edges of the rails 38 and 40 and thereby keep the car on the track.

four Wheels of the car will remain on the track.

A plate 92 rests upon and is secured to the side frame the rectangular frame members 84 and 86 are secured.

By virtue of the wheels at the rear of the car being carried by a swiveled truck, the car can travel on all four wheels over rails which are not necessarily always in a horizontal plane. One rail may be higher at one point than itsparallel corresponding rail and still all It is highly important that all four wheels of the car remain at all times upon the rails because when a succeeding tunnel section weighing well over a ton is supported, as here, forwardly of'the car and is revolved and displaced to position it against the end of the completed portion of the tunnel to form a tubular continuation thereof, as is more particularly pointed out hereinafter, a firm support for the succeeding section is essential if the section is to be accurately positioned and aligned with the end of the completed tunnel. The pivotal support of the rear end of the car upon wheels 46 and 48 will allow for any unevenness of the track and ensure the constant contact of all four wheels of the car with the rails.

As shown in Figs. 22, 23, and 26, a driven sprocket 94 is fixed upon the axle 78 which carries the Wheels 74 and 76. This sprocket is disposed between the bearing blocks and 82. A drive chain 96 passes around this sprocket and up over a sprocket 98 mounted on a shaft 100 which shaft extends across the car and is rotatably supported in hearings on opposite sides thereof on the frame members 66 and 68. A second sprocket 102 is also mounted upon shaft 100. Chain 104 couples sprocket 102 with sprocket 106 mounted on shaft 108 which shaft extends across the car and is rotatably supported in bearings within the frame members 66 and 68. The shaft 108 carries a sprocket 110 mounted thereon opposite a sprocket 114 carried by motor shaft 116. A drive chain 112 passes over sprockets 110 and 114 whereby the mechanism is driven by the motor 118.

Mounted on the shaft 116 adjacent the sprocket 114 is a brake drum 120. A brake band 122, Fig. 22, passes around the drum 120 and may be actuated by linkage 124 to grip the drum. This brake serves as the brake for the car and by locking the brake the car may be held stationary on the track.

As shown in Figs. 25 and 30, and generally indicated as 126, six 12-volt batteries are connected in series with one terminal 128 grounded to the frame of the car. The other terminal 130 leads to the speed control box 132, shown in Fig. 24, through connector 133. To recharge the batteries, the battery charger is coupled to the batteries through connector 133. The speed control box is provided with variable resistors adapted to control the amount of current flowing through the motor, thereby providing a speed control therefor. The batteries 126 lie between the axles of the wheels of the car and are enclosed by the shield 135. A lid 137 mounted upon hinges 139 is adapted to close the battery compartment. The batteries serve in part to counterweight a tunnel section supported ahead of the car.

As shown in Figs. 22 and 23, a plurality of vertical rods 134, mounted upon plate 92 of the car, support a second plate 136 spaced above the plate 92. Inverted L-shaped frame members 137 and 139 support a third plate 141 spaced above the plate 136. At the forward end of the car (Fig. 23) supported upon the plate 92 by the washer 138 is a bearing shaft support 142 for the tunnel section supporting boom generally indicated as 140, Fig. 13. The bearing shaft support comprises the vertical shaft 142 provided at its lower end with a stud 144 which extends through aligned holes in the Washer 138 and the plate 92. The upper end of the shaft exhibits a threaded stud portion 146 with a nut 148 threadedly secured thereto and adapted to lock the shaft to the underside of the plate 136.

9 Eneircling the shaft is a pair of bearing members 150 and 152 each comprising upper and lower halves separated by ball bearings 154 adapted to run in bearing grooves formed in the opposed faces of the upper and lower halves. Journaled upon the shaft between the bearings 150 and 152 is the boom supporting block 156, provided with a bearing sleeve 158 which sleeve bears directly against the shaft 142. The block 156 is thereby rotatably supported on the car through being journaled by hearing sleeve 158 upon the shaft 142 between the bearings 150 and 152.

The tunnel section supporting boom 140 comprises a pair of parallel rectangularly shaped in cross section hollow boom members 160 and 162. These two boom members are welded as at 166, or otherwise secured to the block upon opposite sides of a projection 164 of the block 156 as shown in Fig. 23.

At the rear side of projection 164 is secured the link member 167 which link is pivotally coupled with the hydraulic cylinder and piston combination 168, as shown in Figs. 13 and 25. The opposite end of the cylinder piston combination is swiveled by a pivotal connection 170 to the shield 135. This cylinder piston combination 168 is adapted to swing the tunnel section supporting boom laterally of the car about the shaft 142.

At the outer end of the boom 140 is mounted the tunnel section supporting head 172 shown in Figs. 13, 14, and 15. The head comprises a bracket portion replaceably receivable over the end of the boom and a tunnel ring section supporting portion pivotally mounted upon the bracket. The bracket consists of a vertically extending member 174 and a bracing member 182 connected at its upper end to the top of the member 174 and diverging from member 174 as it extends downwardly until meeting stlut 184, after which bracing member 182 parallels member 174, spaced therefrom by the width of the parallel boom members 160 and 162. The strut 184 is welded or the like to members 174 and 182. Two additional struts 186 and 188 parallel strut 184 and are welded at each end to the members 174 and 182. Struts 186 and 188 are spaced apart by the cross sectional height of boom member 160, with the vertical dimension of strut 188 being such as to permit it to slidably fit within the space between the boom member-s 160 and 162.

By virtue of the particular relationship of bracing member 182 to the member 174, and the interposition of struts 186 and 188 between members 174 and 182 of the bracket, the entire supporting head 172 may be slidably received upon the end of the supporting boom. Such slidable connection between the supporting head and the boom permits ready interchangeability of supporting heads and allows heads of varying sizes to be mounted on the boom, thereby utilizing the same tunnel section supporting car for handling different sizes of tunnel ring sections.

The overlapping relation of struts 186 and 188 with the parallel boom members is shown in Figs. 14 and 17. Blocks 187 and 189 fixed on the boom members limit the rearward slidable movement of the supporting head. A plate 191 welded inside the end of boom member 160 is adapted to threadedly receive a hook 193. A bar 195, receiving therethrough the shank of hook 193 overlies the end of boom member 160 and is adapted to overlie the edges of bracket members 1 4 and 182, there by detachably securing the supporting head to the end of the boom. The hook 193 is also adaptedto be coupled to a mud car so that the tunnel section supporting car may be employed as a locomotive to haul the mud car, loaded with earth removed from the heading, out of the tunnel.

This bracket assembly mounted on the end of the boom carries the tunnel ring section engaging and supporting mechanism. Fixed to the lower end of the bracket member 174, as shown in Fig. 14, is an L-shaped bearing bracket 190. At the opposite or upper end of the member 174 is fixed a bearing block 192. Intermediate the heating bracket 190 and the bearing block 192 is fixed a second bearing block 194. The bearing blocks 192 and 194 and bracket 190 are adapted to rotatably support a vertical shaft 176. Approximately midway between the ends of shaft 176 is fixed a part 196 provided with a horizontal stub axis or spindle 198 over which is rotatably mounted a hub 200 which hub carries tunnel ring engaging arms 178 and 180. A nut 202 is threadedly received over the reduced end of the spindle 198 and is adapted to hold the hub thereon. The spindle is provided with a flange 199 and a hub supporting portion 201 adjacent to the flange as shown in Fig. 14.

The rotatable shaft 176 is also axially slidable within its mounting on the bracket. A part 284 is telescopically received in the lower end of shaft 176 as shown in Fig. 18, and the shaft is adapted to reciprocate linearly of the part. This part 204 is seated at one end upon the bracket 190. The part 204 and associated mechanism is adapted to impart slidable movement to the shaft 176. The details of the .part 204 in the lower end of the shaft 17 6 are shown in Fig. 18. The shaft is interiorly bored out as at 286 to receive the part 284. The part itself is interiorly bored out as at 287 to receive slidably the plunger 208. The plunger at its upper end is tapered as at 218. The upper end of the bore 206 in the shaft is shaped to complement the upper end of the plunger to form therewith a bearing contact such as illustrated at 211.

The lower end of the plunger 208 is provided with packing 212 which encircles the plunger and bears against the inside wall of the bore 287 of the part 284. A hydraulic line 214 communicates with the interior of the bore 287 of part 204 at the lower end thereof and is adapted to feed hydraulic fluid into the bore and urge the plunger 208 upwardly to raise the shaft.

As can now be readily appreciated, if hydraulic fluid is fed through line 214 to the part 204, the shaft 176 will be slidably raised, carrying with it the spindle 198 and the hub 280 with its arms 178 and 180. Because the shaft 176 is rotatably as well as slidably mounted in the bearing block-s 192 and 1%, and because the hub 20% provided with the arms 17S and 1811 is rotatably mounted upon the spindle 198, and because the boom itself is laterally swingable, substantially universal movement of a tunnel ring section, carried by the arms 178 and 189 about and along a plurality of axes, may be accomplished.

More specifically the arms may be revolved about the horizontal axis of spindle 198, which horizontal axis may be vertically displaced through raising and lowering shaft 176. Such horizontal axis is also revolvable about the axis of shaft 176 parallel to the line of vertical displacement thereof. When together with such universal movement of arms 178 and is also considered the lateral displacement of the boom 141), it can be appreciated that a succeeding tunnel ring section supported on the arms 178 and 180 can be tilted and rotated both about horizontal and vertical axes and also bodily displaced along horizontal and vertical axes. Therefore universal movement may be imparted to a tunnel ring section mounted upon arms 178 and 180.

The ring engaging arms 178 and 188 are shown in Fig. 15. To couple a tunnel ring section to the arms, each arm is provided at its free end with a washer 216. The washers are fixedly mounted upon the arms and are adapted to support the weight of a tunnel section upon the arms. Each of the arms is interiorly bored out to slidably receive plungers 218 and 2251. Each of the plungers is provided with a pin 222 which extends through a slot 224 formed in each of the arms. Each slot is shaped at its opposite ends to provide an offset portion 226 and into which the pins may be seated to lock the plungers in either retracted or extended positions. The plungers are spring urged within the arms by coil springs 228 and 238 out wardly of such arms.

As shown in Figs. 1, 2, and 15, each of the tunnel ring sections is provided with a pair of apertures or recesses 232 diametrically opposed and spaced midway between tioned in each ring section, when the plungers 218 and a 220 are introduced thereinto, the section is rotatably supported at its center of mass by the hub upon the spindle 198. The section is also tiltably supported upon the plunger 218. The washers 216 take the weight of the section when it is in the position shown in Figs. 13, 14, and 15. The plungers keep the section properly positioned upon the arms 178 and 180. At any position of rotation of the section it is supported at its center of mass. Such manner of support enables a section weighing well over a ton to be easily revolved about the spindle 198 by one man. A bearing 233, encircling the spindle 198 fastened as at 234 to the hub, ensures the easy revolution of a heavy tunnel section.

A pair of stops 236 and 238 mounted respectively upon bracket bearings 192 and 190 adjacent the top and bottom of the shaft 176 serve to keep the arms 178 and 180 in the position shown in Fig. l3, l4, and 15 as a succeeding tunnel ring section is being carried through the already installed portion of the tunnel. Each of the stops is provided with a spring loaded plunger 240 having an actuating and locking pin 242, and a slot 244 formed in the wall of the stop to receive therethrough the actuating and locking pin (Fig. 16). Each slot exhibits at its opposite ends an offset portion into which the pin may be moved to lock the plunger in the extended or retracted position. The plungers of the stops when extended abut the arms 178 and 180 on the same side of the axis of revolution of the arms so that when the plungers are in their extended positions the arms will not be permitted to revolve about the spindle 198.

As an alternative to the use of these stops to prevent revolution of the arms 178 and 180, a chain such as that shown in Figs. 28 and 29 may be employed. It is to be understood that with the use of this chain the stops shown in Figs. 14 and 16 need not be employed in the supporting head. The stop 236 is completely eliminated. The stop 238 is replaced by a fixed bar 246, or rod, which is mounted as is stop 238 to the underside of bracket 190, as shown in Fig. 28. The bar extends to a position such that it abuts arm 180 when it is in the vertical position shown. A chain 248 is coupled by a. link 250 to the arm 178. The chain extends around the tunnel section mounted on the arms 178 and 180 and is removably coupled at its other end, through a bracket 252 mounted on plate 141, to the car as shown in Fig. 29.

The bracket is provided with a V-shaped notch (Fig. 29) into which one link of the chain may be dropped to lock the chain to the bracket. A coil spring 254, having its ends fastened to the chain with a slack portion of the chain between the ends of the spring, is adapted to maintain a tension on the chain and hold the tunnel ring section in the position shown in Fig. 13. The chain and spring exert a tension which tends to revolve the arms 178 and 180 in a direction such that the arm 180 is constantly held against the bar 246. The chain also tends to prevent the tunnel ring section and the shaft 176 from revolving about a vertical axis. The chain tends to hold the ring section against the supporting boom 140 and keep it from bumping against the inside of the completed tunnel as the section is carried therethrough.

The rear end of the car is weighted as at 260 behind the cockpit generally indicated as 262, to counterbalance the weight of a tunnel section suspended ahead of the car. Within the cockpit are the control levers for operating movement of the car and of the tunnel section supporting head. The brake lever 264 is coupled with the link I mechanism 124, shown in Fig. 23 and upon actuation of the brake lever the car may be locked in one position on the track. A speed control lever 266 is coupled with the variable resistors within the speed control box 132 and the speed of the car may be controlled by this lever.

The lever 268 is coupled with the piston of the hydraulic pump 270 shown in Figs. 24 and 27. Upon actuation of this lever, hydraulic fluid pressure is built up within the pump and the fluid under pressure is led through a line 272 into a valve 274 and thence into the cylinder piston combination 168. With the valve 274 in the position shown in Fig. 27, hydraulic fluid from the pump enters the cylinder-piston combination to urge the piston thereof outwardly of the cylinder and thereby move the supporting block 156 and laterally position the tunnel section supporting boom 140.

The tunnel section supporting boom is moved in the opposite direction by a reversal of valve 274 from the position shown in Fig. 27 to one in which hydraulic fluid from pump 270 passes through line 272 and thence through line 276 into the opposite end of the cylinderpiston combination. A valve 278 is provided in the line 280 through which exhaust fluid from the cylinderpiston combination is led to the reservoir 282. This valve is adapted to maintain a back pressure against the piston such that the piston may be locked in any desired position merely by closure of the valve 278. When the valve 278 is closed and a pressure is built up in pump 270, hydraulic fluid cannot escape from the cylinder-piston combination and the piston will be locked in position. The reservoir 282 feeds the fluid through line 284 to the pump 270.

The piston of a second pump 286 is adapted to be actuated by the lever 288. This pump is connected by line 290 to valve 292. The line 214 leads from valve 292 to the part 204 at the lower end of the shaft 176 in the tunnel section supporting head. Upon actuation of the pump by lever 288, and with the valve 292 in the position shown in Fig. 27, the plunger 208 in the part 204 in the tunnel section supporting head is raised and the shaft 176 consequently raised. With a tunnel ring section mounted on the arms 178 and 180, upon actuation of the lever 288 the tunnel ring section is raised.

A second line 294 extends from valve 292 back to the reservoir 282. This line is a drain for the hydraulic fluid within the bore 207 of the part 204 which has raised the plunger. With the valve 292 rotated approximately from the position shown in Fig. 27, the hydraulic fluid will pass under pressure of gravity back through line 214, through valve 292 and line 294 into the reservoir.

It will be understood that the hydraulic system shown in the various figures of the drawings, and above described, is merely an illustrative embodiment and a mechanical linkage might equally well be used in its stead.

In the operation of the tunnel ring supporting and positioning apparatus shown in Fig. 13, and in the method of laying sections by my improved process, a large shaft is first sunk in the ground. An earthen tunnel long enough to receive one length of tunnel ring section is then dug to one side of the shaft. A tunnel ring section is then lowered down the shaft and placed in the earthen tunnel with the major axis of the section vertical, the minor axis horizontal, and the tubular axis extending in the direction the tunnel is to run. Earth is then dug out from ahead of this installed section forming a heading. The installed section may then be jacked into this heading and a succeeding section placed in the earthen tunnel behind the installed section with the corresponding axes of the sections aligned. The operation is then repeated until a plurality of tubular sections have been thus installed.

Thereafter the track is lowered down the shaft and placed on the bottom of the installed sections with a portion of the track extending across the bottom of the shaft. The car is then lowered down the shaft and placed on the track with the boom of the car extending toward the eye of the installed portion of the tunnel. A mud car is lowered down the shaftand placed on the track and coupled to the tunnel section supporting car by the hook 193 on the end of the boom. The operator, then sitting in the cockpit 264, runs the tunnel section supporting car into the installed or completed portion of the tunnel pushing ahead of it the mud car. A heading is dug ahead of the completed tunnel suificient to receive one or more lengths of tunnel ring sections, with the removed earth being loaded into the mud car. The tunnel section supporting car then draws the mud car out of the tunnel and thereafter the mud car is lifted out of the shaft.

Following removal of the mud car, a tunnel ring section is lowered down the shaft. The ring section is seated on the track between the car and the eye of the tunnel with the tubular axis of the section paralleling the rails of the track. The actuating and locking pins 222 mounted in the arms 178 and 180 are moved in their slots to retract the plungers 218 and 220 which are locked in the retracted positions. The car is then run forward until the supporting head is within the tunnel ring. The plungers 218 and 220 are aligned with the recesses 232 and the actuating pins 222 released, permitting the rods 218 and 220 to snap into locking engagement with the recesses of the tunnel ring section.

With the tunnel section so mounted on the arms 178 and 180, the pump 286 is actuated and hydraulic fluid is fed to the part 204 in the tunnel section supporting head. The supply of fluid to part 204 serves to slidably raise the shaft 176, and through the spindle 198 and the arms 178 and 180, also to raise the tunnel section off the track. The tunnel section While so supported is then revolved so that it is suspended above the track, as shown in Fig. 13 with its major axis parallel the tubular axis of the completed portion of the tunnel.

If the steps shown in Figs. 14, 15, and 16 are employed in the supporting head, the spring loaded plungers are released by their actuating pins 242 and the arms 178 and 180 are locked in the position shown in Figs. 14 and 15. If the chain 248 is employed, one end is hooked over the ring 250 and the other end carried back to and, after a tension is created in the spring 254, hooked in the bracket 252.

The pump 270 is now actuated to laterally move the boom and carry the tunnel ring into alignment with the eye of the tunnel to be moved therethrough. The car is then run through the completed portion of the tunnel carrying the tunnel section ahead of it suspended above the track, as shown in Fig. 13.

It is to be noted that the tunnel section while so suspended ahead of the car by the boom, is suspended ahead of the point of the weight of the tunnel section upon the floor of the completed tunnel. The tunnel section is also, While so suspended, carried at its center of mass as hereinabove mentioned, and is revolvable and displaceable along both its horizontal and vertical axes.

When the car has moved the tunnel section into the heading, the actuating pins 242 are moved to retract the spring loaded plungers of the stops, if the stops are employed. If the chain is used, the end thereof fastened to the bracket 252 is released. The tunnel section is then revolved about the spindle 198 until the major axis of the section is parallel to the major axes of the tunnel ring sections comprising the completed portion of the tunnel. The section is then revolved about the axis of shaft 172 in the supporting head until the minor axis of the section is parallel to the minor axes of the ring sections of the completed portion of the tunnel. Then through combined lateral movement of the boom and slidable movement of the shaft 172, the tunnel section is brought into tubular alignment with the completed portion of the tunnel. The suspended section may be tilted as well as rotated and shiftably displaced laterally and vertically. When accurately aligned, the car is moved as though to back it out of the tunnel. Such movement of the car carries the suspended'tunnel section back against the end of the completed portion of the tunnel to form a tubular continuation of the heading. Not only thereof. The backing movement of the car to carry the suspended tunnel section against the end of the completed tunnel is accomplished with sufiicient force to ensure a tight seal between the meeting edges of the suspended section and the terminal end section of the completed tunnel. Suitable joint sealing compound may be employed if desired.

It may also be noted that the car may be moved so that the suspended tunnel section is positioned within two or three inches of the end of the completed portion of the tunnel and then a final adjustment of position of the suspended tunnel section may be accomplished, thereby ensuring accurate alignment of the suspended section with the-terminal end section of the completed tunnel. Rapid acceleration of the car in a direction as though to back it out of the tunnel causes the suspended section to be jammed against the end of the completed portion of the tunnel thereby ensuring a tight seal between the suspended section and the terminal end section of the completed portion of the tunnel.

The actuating pins 222 are then moved to retract the rods 218 and 220 and the arms 178 and 180 are thereby uncoupled from the section. The car is then backed out of the tunnel and the operation repeated.

From a consideration of Figs. 1, 2, 3, l3, and 3133, and the foregoing description, it will be noted that the tunnel ring section supported ahead of the car, is capable of movement upon the supporting boom from a position wherein the tubular axis of the tunnel ring is disposed substantially perpendicular with respect to a longitudinal plane of the boom to a position wherein the tubular axis of the ring is disposed substantially parallel to a longitudinal axis of the boom. Such movement occurs when the tunnel ring section is moved from the position shown in Fig. l to the position shown in dotted outline in Fig. 2. Such movement is also shown when a tunnel ring section is moved from the position shown in Fig. 31 through the position shown in Fig. 32, to the position shown in Fig. 33. In Fig. 31 the tubular axis of the ring is disposed perpendicular to a longitudinal plane of the boom 140. In Fig. 32 the tunnel ring has been rotated about an axis substantially perpendicular to a longitudinal plane of the boom, and in Fig. 33 the tunnel ring has been rotated from the position of Fig. 32, to one in which the tubular axis is substantially parallel to a longitudinal plane of the boom.

With the methods hereinabove described for positioning a succeeding tunnel ring section against the leading edge of the already installed portion of the tunnel, the length of the heading, and therefore the space ahead of the tunnel within which the succeeding section may be rotated, has not been a consideration. When the ground through which the tunnel is being constructed is quite firm, as, for example, where it is clay, a heading of considerable length may frequently be dug and then a number of succeeding tunnel sections added to the leading edge of the tunnel before the heading must be again lengthened. However, where the ground is soft or sandy, and the roof of the heading threatens to cave in, the heading must be as short as possible to minimize the length of the unsupported roof of the heading between the upper leading edge of the tunnel and the wall at the end will a short heading decrease the length of the unsupported roof of the heading and therefore tend to prevent the roof from caving in, but in addition a short heading may be dug avhile the workmen remain within the protection of the completed portion of the tunnel.

However, where the heading is to be made short, it requires a somewhat different method of rotation of the succeeding section at the leading end of the tunnel to align the section with the tubular axis of the completed portion of the tunnel. In Figs. 3639 are shown three methods of rotating and positioning the succeeding tunnel section Where the heading is kept to a minimum lengthconsistent with certain dimensions of the succeeding tunnel section. I have found that the succeeding section may be rotated from the position shown in Fig. 36 to the dotted outline position of Fig. 37 when the heading is of a length no greater or not substantially greater than the minor diameter or axis of the succeeding section. In the description of the following three methods it is to be understood that the heading which is dug ahead of the leading edge of the completed portion of the tunnel may be of substantially this length.

The apparatus for carrying out these three methods is schematically shown in Figs. 1-4, while the commercial form is shown in Figs. 36-39, in which the apparatus is substantially the same as that described in connection with Figs. l3-30. The apparatus shown in Figs. 36-39 differs from the apparatus shown in Figs. 13-30 in that the tunnel section supporting boom is longer in Figs. 3639 than in Fig. 13, and the supporting head at the end of the boom has the bearings displaced slightly as noted hereinafter. In Figs. 36 and 39 the boom 140 is sufiiciently long that a workman M can stand between the forward end of the car and a tunnel ring section 20 supported on the end of the boom by the supporting head 172 and can manipulate the tunnel ring while standing within the protection of the completed portion of the tunnel.

According to the first of these three methods, and as shown in Figs. 36 and 37, the heading H is enlarged as at 298 along its length so that the roof of the heading lies above the roof line of the already installed portion of the tunnel. A tunnel section 20 is then carried in the hereinbefore described manner through the completed portion of the tunnel and partially into the heading. Thereupon the workman rotates the section about its tubular axis in a counterclockwise direction as viewed in Fig. 37 while the operator of the tunnel car 42 simultaneously elevates the section by the supporting head 172 and as necessary inches the car forward toward the heading. By simultaneously rotating, elevating, and moving the succeeding tunnel section forward, the section may be rotated about its tubular axis closely adjacent and pivoted about the upper meeting edge 300 of the terminal installed section while the bottom of the succeeding section is swung clear just above the track 37 in the bottom of the tunnel. During the elevating, rotating, and advancing of the succeeding tunnel, the upper or roof portion of the section is swung into the excavation at 298 in the roof of the heading. This excavation 298 permits the succeeding section to be elevated a greater amount than would be possible if the heading had a roof line equal to no greater height than the roof line of the already installed portion of the tunnel. As this elevating, rotating, and advancement of the section is continued, the section is eventually disposed in a position similar to the dotted outline position of the section in Fig. 37, except that the major diameter of the section is vertical, the section having already passed through the solid outline position shown. Thereafter the ring is rotated about its major axis or diameter and lowered to align its tubular axis with the tubular axis of the terminal installed section, and is then withdrawn against the leading edge of the tunnel to form a tubular continuation thereof.

As shown in Fig. 37, the bearing blocks 192 and 194, in the supporting head 172 are disposed higher relative to the boom 140 than the bearing blocks 192 and 194 in Fig. 14, and the piston 204 is longer than piston 204 in Fig. 14, with the result that the tunnel section may be elevated a greater amount than with the structure shown in Fig. 14. In other respects head 172 is similar to head 172.

Instead of excavating the heading along the roof as at 298, the floor of the heading may be lowered by excavating it similar to the manner of the excavation of the roof, and the succeeding tunnel section may be rotated about and close to the lower leading edge of the terminal in- 16 stalled section similar to the manner of its rotation about the upper leading edge, as above described. In this latter case the bearing blocks 190 and 192 would be set lower relative to the boom than their position in Fig. 14, instead of higher as shown in Fig. 37.

A second method of rotating the succeeding tunnel section while the heading is kept as short as possible is shown in Fig. 38. This method is similar to that shown in Figs. 36 and 37 except that instead of excavating the roof of the heading as at 298 throughout the length of the heading, the roof is simply scalloped or cut away in a localized area as at 302 adjacent the upper leading edge 300 of the terminal installed section, and the upper end of the tunnel section is rotated into this scallop. This scalloped portion of the roof lies spaced slightly ahead of the upper leading edge of the terminal installed section. As the succeeding section nears the end of the tunnel, it is rotated and elevated while being carried into the heading, with the rotation and elevation continued so that it is pivoted about the upper leading edge 300 of the end of the tunnel. In Fig. 38 the section is shown during rotation about its tubular axis, with the top of the section disposed within scallop 302 and the section disposed closely adjacent the upper leading edge 300 of the tunnel.

When the major diameter of the section is substantially vertical the section is lowered and its tubular axis aligned with the tubular axis of the terminal installed section, and the succeeding section then drawn back against the leading edge of the tunnel to form a tubular continuation thereof. The tunnel section supporting head 172 is of the same construction as that described in Fig. 37.

The third method of rotating and positioning a tunnel section against the leading edge of the tunnel when the heading is kept as short as possible is shown in Fig. 39. According to this method the heading is scalloped out as at 304 in the floor 306 of the heading. A tunnel ring carried by the boom 140 in the manner shown in Fig. 36, is moved through the tunnel and at the leading edge thereof is rotated clockwise, as viewed in Fig. 39, about its tubular axis and lowered slightly so that the section is kept closely adjacent the lower leading edge 308 of the tunnel during the clockwise rotation. The lower end of the section rotates through and is disposed within the scallop 304 when the section reaches that position of rotation in which the major diameter is substantially vertical. Thereafter the section is elevated and rotated about its major diameter and disposed in tubular alignment with the end of the tunnel and Withdrawn back against the end of the tunnel to form a tubular continuation thereof.

The tunnel section supporting head shown in Fig. 39 is of substantially the same construction as the head 170 shown in Fig. 14 except that here the bearing blocks 192 and 194 are set lower with respect to boom 140 in Fig. 14, so that a greater permitted lowering of a tunnel section supported on the head may be accomplished.

What I claim is:

1. That method of constructing a tunnel from a plurality of similarly dimensioned tubular tunnel sections each having a major axis and a minor axis and each hav ing an outside dimension along its minor axis less than the inside dimension along its major axis and having a tubular axial dimension such that one tunnel section may be passed through another tunnel section when the corresponding axes of the two sections are disposed substantially perpendicularly with respect to each other comprising: installing a succession of said sections in tubular alignment forming a length of tunnel, removing the earth from ahead of the length of tunnel forming a heading suflicient to receive a succeeding tunnel section, supporting a succeeding tunnel section so positioned with respect to the installed sections that the corresponding axes of the succeeding section and the installed sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections, advancing the succeeding section while so supported through the installed sections and into the heading, supporting the succeeding section at its center of mass within the heading but with the weight of its support taken from a point Within the installed sections rearwardly of such heading for rotatable and radial displacement sufficient to bring the succeeding section into tubular alignment with the installed sections, displacing said section within the heading while so supported from within the installed sections bringing its several axes into alignment with the corresponding axes of the installed sections, and withdrawing the succeeding section when so aligned toward the installed sections forming a tubular continua tion thereof.

2. That method of constructing a tunnel from a plural ity of similarly dimensioned tubular tunnel sections each having a major axis and a minor axis and each having an outside dimension along its minor axis less than the inside dimension along its major axis and having a tubular axial dimension such that one tunnel section may be passed through another tunnel section when the corresponding axes of the two sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections comprising: installing a succession of said sections in tubular alignment forming a length of tunnel, removing the earth from ahead of such length of tunnel forming a heading sufficient to receive a succeeding tunnel section, interiorly supporting the succeeding tunnel section upon wheeled supporting and positioning apparatus with the succeeding section disposed forwardly of its wheeled support and supported at substantially its center of mass for rotation about and displacement along a plurality of its axes, positioning the succeeding section while so supported such that corresponding axes of the succeeding section and the installed sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections, advancing said wheeled supporting and positioning apparatus while so supporting the succeeding section through the installed sections until the succeeding section is advanced into the heading but with the wheeled supporting and positioning apparatus taking the load thereof within the installed sections, revolving and displacing said succeeding section within the heading about its center of mass and upon its support by the wheeled apparatus bringing its axes into alignment with the corresponding axes of the installed sections, and withdrawing the succeeding section when so aligned toward the installed sections forming a tubular continuation thereof.

3. That method of constructing a tunnel from a plurality of similarly dimensioned tubular tunnel sections each having a major axis and a minor axis and each having an outside dimension along its minor axis less than the inside dimension along its major axis and having a tubular axial dimension such that one tunnel section may be passed through another tunnel section when the corresponding axes of the two sections are disposed substantially perpendicularly with respect to each other comprising: installing a succession of said sections in tubular alignment forming a length of tunnel, removing the earth from ahead of the length of tunnel thereby forming a heading sufiicient to receive a succeeding tunnel section, interiorly supporting a succeeding tunnel section so positioned with respect to the installed sections that the corresponding axes of the succeeding section and the installed sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections, advancing the succeeding section while so interiorly supported through the installed sections and into the heading, supporting the weight of said succeeding section when disposed within the heading from a point of support within the installed sections and in such a manner that such succeeding section may be shifted along a plurality of axes and rotated about a plurality of axes to bring the same into tubular alignment with the installed sections, while so interiorly supporting the succeeding section and with its weight supported from within the installed sections shifting and rotating the succeeding section within the heading bringing it into tubular alignment with the installed sections and into abutting continuation therewith.

4. That method of constructing a tunnel from a plurality of similarly dimensioned tubular tunnel sections each having a major axis and a minor axis and each having an outside dimension along its minor axis less than the inside dimension along its major axis and having a tubular axial dimension such that one tunnel section may be passed through another tunnel section when the corresponding axes of the two sections are disposed substantially perpendicularly with respect to each other comprising: installing a succession of said sections in tubular alignment forming a length of tunnel, removing the earth from ahead of the length of tunnel forming a heading sufficient to receive a succeeding tunnel section, supporting a succeeding tunnel section so positioned with respect to the installed sections that the corresponding axes of the succeeding section and the installed sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections, advancing the succeeding section while so supported through the installed sections and partially into the heading, supporting the succeeding section disposed partially within the heading and partially within the installed sections with the weight of the support taken from a point within the installed sections for rotation about its tubular axis, rotating the succeeding section about its tubular axis while so supported and disposed with respect to the heading and the installed sections and concurrently advancing the succeeding section into the heading while maintaining the succeeding section in close proximity with that edge of the terminal installed section adjacent the heading and continuing such rotation and advancement of the succeeding section until the major axes of the succeeding section and installed sections are substantially parallel, displacing the succeeding section while so supported from within the installed sections bringing its several axes into alignment with the corresponding axes of the installed sections, and withdrawing the succeeding section when so aligned toward the installed sections forming a tubular continuation thereof.

5. That method of constructing a tunnel from a plurality of similarly dimensioned tubular tunnel sections each having a major axis and a minor axis and each having an outside dimension along its minor axis less than the inside dimension along its major axis and having a tubular axial dimension such that one tunnel section may be passed through another tunnel section when the corresponding axes of the two sections are disposed substantially perpendicularly with respect to each other comprising: installing a succession of said sections in tubular alignment forming a length of tunnel, removing the earth from ahead of the length of tunnel forming a heading sufficient to receive a succeeding tunnel section, supporting a succeeding tunnel section so positioned with respect to the installed sections that the corresponding axes of the succeeding section and the installed sections are disposed substantially perpendicularly with respect to each other and the major axis of the succeeding section is disposed substantially parallel to the tubular axis of the installed sections, advancing the succeeding section while so supported through the installed sections and partially into the heading, supporting the succeeding section disposed partially within the heading and partially within the installed sections with the Weight of the support taken 

